Fluid-operated pump



Feb. 14,1950

M. F. ECKER FLUID-OPERATED PUMP s SheetS-Sheet s rill/ 7 47!!! w v a Filed July 13, 1947 INVENTOP: MURRAY E'EcKER ,Feb. 14, 1950 M. F. ECKER 2,497,348

FLUID-OPERATED PUMP 6- SheetsSheet 5 Filed July 18, 1947 .ZA/vEA/Tok: MURRAY FEcKER a Y HIS A ITOMVEYJ Ham/s, MECH. Fos TER- 8 HA m/s Feb. 14, 1950 M. F. E .IZKER FLUID-OPERATED PUMP 6 Sheets-Sheet 6 Filed July 18 1947 I PILOT VALVE/ JvvE/VmR: MURRAY F E eke/e By HIS Arromvgyg HAPRISJOECILI-YJSTERJHAPRIS WW k5 thereto.

Patented Feb. 14, 1 950 UNITED STATES PATENT or'ncs FLUID-OPERATED rum Murray F. Ecker, Huntington Park, Calii'., as-

slgnor to Pacific Pumps, Inc., Los Angeles, Calif., a corporation of California Application July 18, 1947, Serial No. 761,977

18 Claims. (Cl. 103-46) type have a special utility in the oil industry, and

my invention will accordingly be described in that connection, although its usage is not limited Because of spatial limitations in the casing string of an oil well, designers of fluid-operated pumps have been constantly faced with problems of how to incorporate in a structure, which must of necessity be long and extremely narrow and situated in the depths of the well, many of the refinements, simplifications, and economies which are possible in pumping units which have a simple underground pump mechanically driven from a surface power unit. While fluid-operated pumps possess certain inherent advantages over mechanically driven pumps, it has been difflcult to realize the full scope of these advantages. The basic fact that the fluid-operated motor was frequently in communication with well fluid containing sand or other foreign materials and was usually submerged in such fluid has either required a construction of extreme ruggedness and simplicity or the incorporation of protective devices, such as packings, which added to the friction load. Keeping the motor clear of injurious foreign matter and at the same time keeping it within narrow limits of size has involved compromises, such as constructing a pump capable of pumping in only one direction of reciprocation or incapable of high speeds because of possible injury to reciprocating parts and incapable of low speeds because of impositiv valve action subject to friction. In some instances, springs have been used to assist the motor valves to pass through dead center positions, but such devices add to complexity, bulk, and the liability of mechanical failure.

A principal'object of my invention is, accordingly, to provide a fluid-operated pump of simple construction, having few moving parts and so arranged, as to require a minimum of cross-sectional area and to be capable of being installed in a well casing of ordinary construction and size.

Among the characteristics most sought in any pump unit is the ability to pump well fluid on both strokes of reciprocation. This ability not only increases the productivity of the pump but reduces the power consumption per unit of product by having no waste motion and by reducing the inertia of the surges of the product in the pipe line to the ground surface. It is accordingly 2 another object of my invention to provide a fluidoperated pump having a double-acting pumping unit operated by a motor receiving a positive application of power coincident with each-stroke of the pump.

It is a further object of my invention, also with a View to eliminating waste motion and surges, to correlate the power applicable to the motor and the discharge of spent operating fluid from the motor on each stroke thereof to the discharge of well fiuid from the pump on the corresponding stroke. I accomplish this purpose by providing a reciprocating motor of the differential-area plunger type and a reciprocating pump, also of the differential-area plunger type, and connecting the plungers by a piston rod which enters into a power cylinder of the motor and into the discharge cylinder of the pump and thereby relates both the power and discharge capacity of the motor and the discharge capacity of the pump to its cross-sectional area.

Another object of my invention is to provide means for minimizing the discontinuity of flow at the end of each stroke of reciprocation of the motor and pump, and particularly for maintaining continuity of flow from the motor, with a view not only of reducing the surge efiect, but of providing hydraulic rather than mechanical means of keeping the motor flushed and clear of foreign matter.

A further object of my invention is to provide hydraulically actuated valve means for causing reversal of direction of the motor and the pump whereby the movement of the valve means itself may be cushioned hydraulically, as well as the movement of the motor and pump plungers and the discharge of the fluid actuating the valve means may be utilized to supplement the total fluid discharge when the latter is at a minimum.

Yet another object of my invention is to provide main valve means entirely hydraulically actuated and therefore gentle in their operation and application, and pilot valve means mechanically, and therefore positively, actuated to assume positions in which they cause hydraulic completion of their own movement and hydraulic actuation of the main valve means.

It is also an object of my invention to provide a fluid-operated pump in which the discharge from the motor is continuous although composed of discontinuous fractions, and the discharge from the pumping unit is .emi-continuous, with the two discharges joining o flow through a common conduit and so arranged that the discontinuous fractions of the motor discharge are united to form a continuous discharge before joining the pumping unit discharge so as to prevent the entry of the latter into the motor.

Still another object of my invention is to provide a fluid-operated motor having hydraulically operated valve means for reversing the direction 01' movement of a, motor plunger, in which the valve means and the plunger are so constructed --as-to--reg'u1ate hydraulically the velocity of the valve means and the deceleration and acceleration of the motor plunger consequent upon movement of the valve means.

Further objects and advantages of the invention will be made evident throughout the following specification and from consideration of the accompanying illustrative drawings, in which:

' Fig. 1 is a vertical sectional view of the upper end 01' my invention as installed in a production to form a jacket 33. The Jacket 33 is of tubular form so as to fit loosely within a production tubing 34 with allowance for an annular space 35 therebetween. The production tubing 34 in turn is of such diameter as to be easily insertable in a well casing 35, indicated in broken lines in Fig. 6.

As shown in Fig. 1, an upper tubular fitting 31 connects the jacket 33 to the lower, end of a fluid supply tubing 38 by which operating fluid under relatively high pressure is delivered to the fluid motor unit 3 As shown in Fig. 4, the production tubing 34 is provided at its lower end with a shoe 39 through which a reduced diameter portion 40 01 the jacket 33 extends downwardly into the well casing 33. Corresponding chamfered shoulders 4| and 42 on the exterior of the jacket 33 and the interior of ----the shoe 39 provide a seat for the fluid-operated tubing, showing the mechanical means for initial- "intermediate portion of my. invention, carried downwardly from the lower end of Fig. 3 and showing the upper or discharge cylinder of the Fig. 5 is a vertical sectional view of a further intermediate portion of my invention,'carried downwardly from the lower end of Fig. 4;

'- -Flg. 6 is a vertical sectional view of the lower end of my invention, carried downwardly from the lower end of Fig. 5, and illustrative of the intake cylinder of the pump and the valve system thereof;

Fig. '7 is a vertical sectional semi-diagrammatic view of the motor unit of my invention, showing the pilot valve ina more advanced position, of operation;

Fig. 8 is a. vertical sectional semi-diagrammatic view similar to Fig. 7, showing both the pilot valve and main valve in another position of operation;

Fig. 9 is a vertical sectional semi-diagrammatic view similar to Fig. 8, showing the pilot valve in a still further advanced position of operation;

Fig. 10 is a cross-sectional view taken on the line ||||li oi. Fig. 1 and on a slightly enlarged scale;

Fig. 11 is a cross-sectional view taken on the line of Fig. 2 and on a slightly enlarged scale;

Fig. 12 is a cross-sectional view taken on the line i2-l2 of Fig. 4 and on a slightly enlarged scale;

Figs. 13 to 24, inclusive, are cross-sectional views taken on the corresponding lines |3l3 to 24-24 of Fig. 3 and on a slightly enlarged scale;

Fig. 25 is a graph showing one method of the operation of my invention under normal operating conditions; and

Fig. 26 is a diagrammatic view of my pump, 11- lustrating the main components thereof, but greatly simplified to clarify the general construction.

Referring to the drawings, I show a fluid-operated pump 30 having a. fluid motor 3| (Figs. 1, 2, and 3) and a pump unit 32 (Figs. 4, 5, and 6), the outer portions or which are threadedly joined pump 30. The jacket 33 is sealed relative to the production tubing 34 by packing cups 43 compressible by spacer rings'44 and a gland 45 (see Fig. 5) threaded on the portion 45 of the jacket 33. It will be understood that the fiuid supply tubing 33 and the production tubing 34 extend upward throughthe well casing 35 to the ground surface, providhig, respectively. a downward con- ..duit tor'operatlng fluid from a, surface pumping I unit (not shown) and an upward conduit for well fluid to which, as will be shown, the spent operating fluid is added.

The jacket 33 is constructed of a plurality of tubularparts threadedly joined so that they may be disconnected at intervals convenient for access to internal parts. As shown in Fig. 1, a tubular member 41 is threadedly secured at its upper end to the upper fitting 31 and at its lower end is secured by a nipple 48 to a tubular member 49. The upper fitting 31, tubular member 41, and nipple 48 define a high pressure chamber 50 at all times open to the fluid supply tubing 38, so as to receive high ,pressure operating fluid therefrom. As shownin Fig. 2, another nipple 5| is secured to thelower end of the tubular member 49 and cooperates with the nipple 48 to clamp between them a liner 52. An adapter 53 connects the nipple 5| to a tubular member 54, the lower end of which (as shown in Fig. 3) is connected in turn to a tubular element 55 which is provided at its lower end with an adapter 55 having an inwardly turned upper end flange 51. As shown in Fig.4, a similar adapter 53 cooperates with the adapter 55 to clamp between them a liner 59 of less interior diameter than the liner 52. The nipple 5| and liner 52 define the upper end and the adapter 55 and liner 59 define the lower end of a motor cylinder 50. As shown in Figs. 2 and 3, a liner iii, of greater interior diameter than the liner 52 and held. clamped between the adapter 53 and the tubular element 55, forms a sleeve for the motor cylinder but, as will be seen, does not extend to either end thereof. As shown in Fig. 2, the upper end of the motor cylinder 6|! is vented to the annular space 35 within the production tubing 34 by motor discharge ports 62 in the walls oi, the adapter 53. The liner 59 (shown in Figs. 3 and 4) separates the motor unit 3| and the pump 32.

As shown in Fig. 4, extending downwardly from the adapter 58 and secured thereto is a tubular member 63 connecting at its lower end to a seat plug 64. The seat plug 64 has a downwardly extending portion 65 of reduced diameter which forms the upper end of the reduced portion 40 of the jacket 33, and the junction of the upper and lower portions or the seat plug forms the chamthreaded at its lower end to receive the gland 45.

A connecting member 01. threadedly secured to the seat plug 94 below the gland 45, has connected thereto a tubular member 98 encompassing a liner 89 of somewhat larger internal diameter than the liner 59. The liners 59 and 09, respectively, define the upper and lower limits of a pump outlet chamber which (as shown in Fig. 4) is in constant communication with the annular space 35 within the production tubing 34 by ports II in the upper portion of the tubular member 03.

As shown in Fig. 5, the liner 09 is held clamped against the connecting member 61 by a shoulder nipple 12 secured to the lower end of the tubular member 68. Additional jacket-forming members 13, which may be of adapter or collar and nipple type, extend the jacket 33 downwardly to conncction with a tubular member 14, to the lower end of which (as shown in Fig. 6) is secured a valve housing 15. The valve housing 15 has at its lower end an inlet passage 10 communicating with the well casing and closed to prevent outward flow from the interior of the valve housing to the well casing by a standing valve 11. The upper end of the valve housing 15 and the lower end of the lowest jacket-forming member 13 cooperate to clamp between them a liner 1!! which forms the wall of a pump inlet chamber 00 and has a larger interior diameter than the liner 69. The upper end of the liner i9 and the lower end of the liner 59 define, respectively, the lower and upper limits of an intermediate space 3| between the pump inlet chamber 80 and outlet chamber 10, which is vented to the well casing 36 by suitable vents- 02 to permit well fluid to flow in and out of the space 8i as required by the hereinafter described plunger action.

As shown in Fig. 3, a motor plunger 83 is arranged to move reciprocably within the motor cylinder 00 and has a plunger head portion 84 fitting slidably within the liner 6| and a body portion 05 of smaller diameter threadedly connected thereto and proportioned to leave an annular channel 86 within the liner 5|. A collar 81, of the same external diameter as the plunger body 05 and threadedly (secured thereto, extends upwardly from the motor plunger 83 and is secured at its upper end to a tubular piston rod 88 which (as shown in Fig. 1) extends upwardly with a sliding fit through the liner 52 and loosely through the nipple 40 into the high pressure chamber 50. The plunger head 04 divides the motor cylinder 60 into two portions: the upper of which includes the annular channel 86 and the space between the collar 81 and the liner 52 and is constantly open to the annular space through the motor discharge ports 62, and is hereinafter designated as the motor discharge chamber 90; and the lower of which includes the space 9| below the plunger ,head 84 and above the liner 59, and which is hereinafter designated as the alternating pressure chamber 9|, for reasons to be later set forth.

The plunger head 84 and the plunger body 05 are tubular, the former having a large bore 92 and the latter having arelatively small upper bore 93, and a larger lower bore 94 separated by a shoulder 95 at their junction. The'bore 93 is closed at its upper end by a tubular upper plug accuse clamped between the plunger body 85 and the collar 01, and the lower bore 94 is closed at its lower end by a tubular lower plug 98 provided with an annular flange 99 held clamped between the plunger body 85 and the plunger head 84. The lower plug 98 and the plunger head 84 define between them an annular space I00 communicating with the lower portion of the bore 92, and the interior of the lower plug 98 is sealed from the bore.92 by a plug IN. The lower end of the plunger head 84 is provided with an adapter I02 98 provided with an annular flange 91 held the passages I04. Likewise, the annular channel 86 forms part of the motor discharge chamber 90, being always in communication therewith. So, also, the interior I05 of the collar 01 and the interior I06 of the tubular piston rod 88 form a continuation of the high pressure chamber 50.

A plurality of circumferentially spaced, vertical ports I01 in the flange 91 of the upper plug 98 lead from the interior I05 of the collar 81 to an annular groove I08 in the lower face of the flange 91 and thence communicate through a plurality of longitudinal passages I09 in the upper part of the plunger body with a terminal annular groove H0 in the wall of the bore 93 below the upper plug 96. Similarly, a plurality of circumferentially spaced, vertical ports I II in the flange 99 of the lower plug 98 lead from the annular space I00 to an annular groove IE2 in the upper face of the flange 99, and thence communicate through a plurality of longitudinal passages H3 in the lower part of the plunger body 05 with a terminal annular groove II 4 in the wall of the bore 94 above the lower plug 98. A plurality of radial ports H5, hereinafter called the plunger discharge ports, communicate between the annular channel 86 and an annular groove H6 in the wall of the bore 94 abovethe annular terminalgroove H4. The high pressure chamber 50 is, therefore, potentially in communication with the alternating pressure chamber 9I through the ports I01, communicating with the interior I06 or the tubular piston rod 08, annular groove I00, upper plunger longitudinal passages I09, annular terminal groove I I0, bore 93 and bore 94, annular terminal groove I I4, lower plunger longitudinal passages H3, annular groove II2, ports III, annular space I00, and passages I04. The alternating pressure chamber 9I is potentially in communie cation with the motor discharge chamber through the ports, I I I, annular groove I I2, lower plunger longitudinal passages II3, annular terminal groove II 4, groove 94, annular groove Hi, the plunger discharge ports I I5, and the annular channel 09. Y

A main valve I20 is reciprocably carried within the plunger body 85 and has a-lower portion I2I of relatively large diameter slidable within the bore 94 and an upper portion I22 of relatively small diameter slidable within the bore 93. The portions III and I22 have longitudinal dimensions relative to the bores in which they slide such that when the upper end of the portion I22 is in contact with the upper plug 96, the shoulder I23 at the junction of the portions HI and I22 is not quite in contact with the shoulder 95 at the junction of the bore 93 and bore 94, and a space I24 designated as the lower main valve chamber extends between the lower end of the portion I 2I and the lower plug 98. When the lower end of the portion I2I is in contact with the lower plug 99, j

axial bore I26 expanded outwardly at both ends to form conical recesses I21 and I28 which, in efiect, act as extensions and minimum clearance volumes of the lower and upper main valve chambers I24 and I25.

The upper portion I22 of the main valve I20 is provided on its exterior surface with an upper annular channel I29 connected by a plurality of longitudinal valve passages I30 to a lower annular channel I3I on the exterior surface of the lower portion I 2|. The annular channels I29 and I3I are so spaced that when the upper annular channel I29 is in registry with the annular terminal groove IIO, the lower margin of the lower annular channel I3I will be in registry with the lower margin of theannular terminal groove II4, thus providing communication as heretofore indicated from the high pressure chamber 50 to the alternating pressure chamber 9I through the longitudinal valve passages I30. The registering pairs of channels and grooves are, moreover, so placed in their respective main valve and plunger bodies that they are in registry when the upper end of the main valve I20 is in contact with the upper plug 96. The upper end of the upper annular channel I29 is provided with an annular throttling groove I32 which may preferably have the form of a groove continuously annular and of less depth than the upper annular channel I29, or may merely be intermittent segments of such a groove so as to provide an orifice of decreasing and increasing cross-sectional area as it is moved respectively downwardly or upwardly into registry with the annular terminal groove H0, in the one instance registering subsequently to the registering of the upper annular channel I29, and in the other instance in advance thereof. The lower annular channel I3I is wider than the annular terminal groove I I4 with which it registers by an amount equal to the maximum width of the throttling groove I32, the excess in width being disposed on the upper side of the annular terminal groove II4 when the upper annular channel I29 and the annular terminal groove IIO are in registry. Thus, the area of registry of the lower annular channel I3I with the annular terminal groove I I4 is always greater than any corresponding area of registry of the throttling groove I32 with the annular terminal groove "0, and any'restriction then imposed on fluid flow through the longitudinal valve passages I30 will be imposed by the throttling groove I32 and may be calculated from the efiective cross-sectional area thereof.

The lower portion I2I of the main valve I20 is further provided with a wide annular bridge channel I34 so proportioned-and disposed as to open communication between the annular terminal groove I I4 and the plunger discharge ports II5 when the lower end of the main valve I20 is in contact with the lower plug 98 and thereby to open the communication heretofore indicated as potential between the alternating pressure chamber 9| and the motor discharge chamber 90. The bridge channel I34 is provided with a shallow downward extension or governing groove I35, similar in form and in purpose to the throttling groove I32, by which communication with the annular terminal groove II 4 may be gradually opened and closed.

- with the annular channel 86 through a radial orifice I36 (see Fig. 15) in the plunger bodyll spaced slightly below the shoulder 95 and through a restricted radial orifice I31 (see Fig. .14) spaced more closely to the shoulder .95 and arranged to open to the bore 94 through an annular groove I33 adjacent the shoulder 95. The upper end oi the bore 94 thereby forms a dashpot by which the velocityof movement of the main valve I2. both upwardly and downwardly is regulated when the shoulder I23 of the main valve is upwardly of the radial orifice I38.

Radial ports I39 (see Fig. 18) in the plunger body 85 connect each of the lower plunger longitudinal passages II3 to the lower portion of the bore and there communicate with the upperend of a helical groove I40 see Fig. 3) in the wall of the bore so disposed as to have its lower end communicate with the lower main valve chamber I 24 when the upper end of the main valve I29 is in contact with the upper valve stop 96. A

vertical passage I4I leads upwardly from the lower end of the main valve I 20 and connects with an annular groove I42 in the outer surface of the lower main valve portion I22, disposed so as to be in registry with the lower end of the helical groove I40 when the lower end of the main valve I20 is in contact with the lower plug 98. When the main valve I 20 is in this position, the vertical passage MI and the annular groove I42 serve as a bleeder conduit to permit fluid fiow between the lower plunger. longitudinal passages H9 and the lower valve chamber I24, the direction of such flow, of course, depending on the relative pressures prevailing at the ends of the conduit.

The helical groove I 40 has a restricted crosssectional area imposing a resistance to fluid flow therethrough substantially proportionate to the length of the helical groove through which fluid is forced to flow. This resistance is at a maximum when the main valve I20 is in contact with either the upper plug 96 or the lower plug 98, and is nil when the annular bleeder groove I42 is in registry with the radial ports I 39.

The lower plug 98 has in descending order an axial minor bore I43 01' the same diameter as the axial bore I26 of the main valve I20, a major bore I44 separated from the bore I43 by a shoulder I45, and a lower threaded bore I46 in which the plug IOI is retained. The plug IOI has a boss I41 on its upper face of less diameter than the major bore I44 and is inserted in the bore I46 to a depth suflicient to bring the upper face of the plug substantially level with the lower end of the major bore I44, leaving an annular space I48 around the boss I41 extending annularly into the bore I46.

A pilot valve I50 is mounted axially within the main valve I20 and the lower plug 98 and has a tubular pilot valve rod I5I fitting slidably within the axial bore I26 of the main valve and the axial bore I43 of the lower plug and a pilot valve piston head I52 fitting slidably within the major bore I44. The junction of the pilot valve rod I5I and piston head I52 is defined by a shoulder I53, and the piston head has a lower face I54 which, in the lowest position of the pilot valve (as shown in Fig. 3), comes into contact with the boss I41. The pilot .valve piston head I52 delimits within the major bore I44 an upper pilot valve chamber I55 and a lower pilot valve chamber I58, the latter including the annular space I48. An axial passage i51 extends throughout the pilot valve rod I5I and into the pilot valve piston head I52 to a,

chamber 50.- A fitting I58, secured to the upper I end of the pilot valve rod II, carries a striker sleeve I60 by means of a pin SI and spacer I62. The striker sleeve I60 is designed to strike against 'the upper fitting 31 and against the nipple 48 to groove I11 similar to the annular groove I16 for the purpose of communicating momentarily with the annular channel 06 through the lower vent passage I69Yand the radial port I1I as it passes that port in upward and downward movement, as shown in Fig. 7. The lower pilot valve port is disposed adjacent the lower end of the axial passage I51 .in the pilot valve piston head I52.

- 'I'he bore I44 in the lower plug 98 has an annular channel I18 adjacent the shoulder .I 45 from upward movement of the main valve I20, an

upper vent passage I65 (best shown in Fig. 13) is provided in the motor plunger 83, radially connecting the annular channel 86 with an annular groove I66 in the outer surface of the tubularan upper spanning groove I68 capable of spanning between the. upper main valve chamber I and the radial port I61 to permit the discharge of operating fluid from the chamber to the annular channel 86, this position beingvillustrated in Fig. 8. Similarly,-to permit venting of the lower main valve chamber I24, a lower vent passage I69 (best shown in Fig. 20) is provided in the motor plunger. 83 connecting the annular channel 86 with an annular groove I10 on the outer surface of the lower plug 98. A radial port "I leads from the bore I43 of the lower plug 98 to the annular groove I10. A wide annular channel on the outer surface of the pilot valve rod I5I forms a lower spanning groove I12 capable of spanning between the lower valve to the annular channel 86, as shown in Fig. 3.

4 The axial passage I51 in the pilot valve I is I open to the lateral surfaces of the pilot valve by means of an upper pilot valve port I13, an intermediate pilot valve port I14, and a lower pilot valve port I15, all radial to the pilot valve. The

upper pilot valve port I13 is disposed above the upper spanning groove I68 in a position permitting it to communicate with the upper main valve chamber I25 when .the pilot valve I50 is lowered relative to the motor plunger 83, as shown in Fig. 3. It communicates with an annular groove I16 on the outer surface of the pilot valve rod I5I, which permits it to register with the radial port I61 in all positions of rotation as it passes that port in upward and downward movement and so to communicate momentarily through the upper vent passage I65 with the annular channel 86, as shown in Fig. '1. The intermediate pilot valve port I14 is disposed below the lower spanning groove I12 in a position permitting it to communicate with the lower main valve chamber I24 when the pilot valve I60 is raised relative to the motor plunger 83, as

which a radial orifice I19 (also shown in Fig. 21) leads to a longitudinal groove I in the exterior .of the lower plug 88 and communicating with the annular groove I10. The upper pilot valve chamber I55 is thus always open to the annular channel 86 through the lower vent passage I69 and may also be open to the lower main valve chamber I24 through the radial port "I and the lower spanning groove I12 and may also be open momentarily to the axial passage I51 through the radial port "I. Another annular channel I8I, spaced below the annular channel -I18, communicates with the annular space I48 in the lower pilot valve chamber I56 through a pilot valve by-pass passage I82. A third annular channel I83 intersects the pilot valve by-pass I82 and has a shallower annular channel I84 extending in downward continuation which serves as a control channel for governing the movement of the pilot valve I50. The lower edge of the annular channel I84 is at a distance from the shoulder I45 substantially equal to the length of the pilot valve piston head I52. The channel I84 and the lower pilot valve port I15 are so disposed in their respective containing members that when the port registers with the control channel, (as illustrated in Fig. '1), the-pilot valve head shoulder I53 is above the annular channel I83 and, hence, has cut oil the upper pilot valve chamber I55 from communication with the pilot valve by-pass.

The connecting rod I03 fits slidably in the liner 59 through which it extends downwardly into the pump discharge chamber 10. As shown in Fig. 4, within the pump discharge chamber 10, the connecting rod I03 is threadedly connected to the upper end of a tubular pump plunger I90. The pump plunger I is of greater diameter than the connecting rod I03 and extends downwardly through the liner 69 (as shown in Fig. 5), fitting slidably therein, into the intermediate space 8| between the pump discharge chamber 10 and the pump inlet chamber 80, where it in turn is threadedly connected by an adapter I9I to a pump plunger head I92 having a still greater diameter. The pump plunger head I92 fits slidably in the liner 19 and extends downwardly into the pump inlet chamber 80, as shown in Fig. 6. Thepump plunger head I92 is also tubular and has secured to its lower end a valve housing I93. A check valve I94, hereinafter called the travelling valve and similar to the standing valve 11, controls the passage 'of fluid from the pump inlet chamber 80 through an inlet passage I95 to the interior space I96 of the pump plunger head I92 and thence to the interior space I91 (seen in Fig. 5) of the pump plunger I90. As shown in Fig. 4, the upper end of the pump plunger I90 has discharge ports I98 communicat- 1 'ing between the interior space I91 and the pump shown in Fig. 8, and is provided with an annular 75 discharge chamber 10, and it will be seen that communication'is always open from the travelling valve I94 through the pump plunger head and plunger to the pump discharge chamber 10 11 and thence through the ports II to the production tubing 34.

Although plungers, pistons, and rods of various ratios may be used in my invention, I preferably seek an optimum condition, hereinafter explained and described, in which the tubular piston rod 88 has a cross-sectional area equal to one-half the diflerence in cross-sectional area of the motor plunger head 84 and the connecting rod I03, and greater than the cross-sectional area of the latter, and in which the pump plunger I90 has a cross-sectional area equal to one-half the cross-sectional area of the pump plunger head I32 and also greater than the cross-sectional area of the connecting rod I03.

Operation The general operation of my pump can best be understood by reference to Fig. 26. In operation, high pressure operating fluid is forced downwardly through the supply tubing 38 from a surface pumping unit (not shown) so as to actuate the fluid motor unit 3| and, the pumping unit 32 connected thereto, in a manner hereinafter described in detail, but more generally describable as a double-acting cycle 01 reciprocation in which the fluid motor unit 3| develops power on both strokes of reciprocation, and the pumping unit' 32 draws well fluid from the well by one stroke and discharges the well fluid so drawn to the production tubing 34 on both strokes. The spent operating fluid is also discharged to the production tubing 34, and, together with the well fluid, is raised to the ground surface by the action of the pumping unit. The motor plunger 83 is, in eflect, of the diflerential-area typ the upper end thereof, in efl'ect, having a relatively small effective cross-sectional area which is continuously exposed to the high pressure of the operating fluid in the high pressure chamber 50, and the lower end thereof being of relatively large eflective cross-sectional area which is alternately exposed to the high pressure of the operating fluid. The high pressure operating fluid is alternatively conveyed to the lower end of the motor plunger 33 by the operation of the main valve I20. M will be understood, when the alternating pressure chamber 9 I, and, consequently, the lower end of the motor plunger 83, are connected to the relativel low fluid pressure in the annular space 35, the high pressure acting on the upperend of the motor plunger will cause it to perform its downstroke, carrying with it the travelling valve I94. Upon completing the downstroke of the motor plunger 03, the main valve I is automatically thrown, to admit high pressure operating fluid to the alternating pressure chamber 9|, which, in turn, causes the motor plunger 33 to move upwardly on its upstroke. At the end of the upstroke of the motor plunger 83, as will be understood, the main valve I20 is again mechanically thrown, to repeat the cycle.

In the following description it will be assumed that the pump has been in operation, that high pressure operating fluid fllls the supply tubing 33, the high pressure chamber 50, and the tubular pilot valve I50, that well fluid fllls the pumping unit 32 and is available at the standing valve 11, and that the production tubing 34 contains fluid at a. pressure relatively low as compared to the pressure of the operating fluid in the supply tubing 38. It should be borne in mind that the motor discharge chamber 90 and the annular channel 30 are always in communication with the production tubing 34 through the motor discharge ports 62 and, therefore, the fluid in them which, as will be hereinafter'shown, is spent operating fluid, is also at the relatively low pressure prevailing in the production tubing.

The operation of the fluid motor unit 3| will be described as a cycle of reciprocation beginning with the motor plunger 83 in raised position and about to descend, as illustrated in Fig. 3. At this stage of the cycle, both the pilot valve I50 and the main valve I20 are in their low positions relative to the motor'plunger 83, with the fluid pressure in the high pressure chamber 50 exerting a downward pressure on the pilot valve so that the bottom face I54 of the pilot valve piston head I52 bears against the plug I M of the lower plug 80. The upper pilot valve port I 13 is open to the upper main valve chamber I25, and the intermediate pilot valve port I14 and lower pilot'valve port I15 are closed, respectively, by'the bore I43 and bore I44. In this position, high pressure fluid from within the pilot valve can, therefore, only reach the upper main valve chamber I25 through the upper pilot valve port I13 to which it is confined. The high pressure fluid also exerts a downward pressure upon the main valve I20. As the pilot valve head shoulder I53 is below the annular channel I8I the upper pilot valve chamber I55 and lower pilot valve chamber I56 are connected to each other by-the pilot valve bypass I02 and are in communication through the radial orifices I19 and the longitudinal groove I30 with the lower vent passage I89 and the annular channel 86 so that the relatively low pressure of the fluid in the production tubing 34 prevails therein. Similarly, the lower main valve chamber I24 is connected-to the lower vent passage I69 by the lower spanning groove I12, radial port I1I, and annular groove I 10, so that the relatively low pressure of the fluid in the production tubing prevails therein also. Consequently, both the pilot valve I50 and the main valve I20 are held hydraulically in their lower positions relative to the motor plunger 33 as the latter descends in its downstroke.

With the main valve I20 in its low position relative to the motor plunger 83, the motor plunger is urged hydraulically to descend. The

upper annular channel I29 of the main valve, at the upper end of the longitudinal valve passages I30, is below and out of registry with the terminal annular groove I I 0 of the upper plunger longitudinal passages I09, and therefore the high pressure fluid in the high pressure chamber 50 is cut off from access to the lower parts of the motor plunger. The pressure of this fluid is effective upon the total cross-sectional area of the motor plunger at the liner 52, or, in other words, the cross-sectional area of the tubular piston rod 88, to urge the motor plunger downwardly. In this position, the alternating pressure chamber 9! is in communication with the motor discharge chamber 90 and thence to the motor exhaust ports 62 to the production tubing 34, by means of the passages I04, annular space I00, ports III, lower plunger longitudinal passages N3, the plunger discharge ports II5, the main valve bridge channel I34, the annular groove H6, and the plunger discharge ports II5, so as to permit the escape to the production tubing of operating fluid forced from the alternating pressure chamber by the descending motor plunger 03. The pressure in the alternating pressure chamber 3| is therefore the relatively low pressure prevailing in the production tubing 34. It is effective upwardly against the cross-secliner 6|, but is in part balanced by the same relatively low pressure In the motor discharge chamber 90 acting downwardly on the motor plunger and efiective on an area having the cross sectional dimensions of the annulus between the tubiar piston rod 88 and the liner 6|. The net area upon which the relatively low pressure acts upwardly is, accordingly, equal to the crosssectional area of the tubular piston rod 88, and the predominating high pressure in the high pressure chamber 50, acting upon. that same area, forces the motor plunger 83 downwardly.

The initial positions above described are indicated in Fig. 25 by the points of intersection of the lines therein representing movement of the motor plunger 83, the main valve I20, and the pilot valve I50 with the travel axis thereof, and it is to be understood that the positions and subsequent movements indicated for the main valve and the pilot valve in Fig. 25 are relative to the position and movement of the plunger, and not relative to-the motor as a whole. In Fig. 25, the courses of the main valve and pilot valve are projected upwardly on the time axis instead of starting at the origin of coordinates.

The motor plunger 83, during its descending stroke, indicated by the sloped line 20I in Fig. 25;

carries the main valve I 20 and pilot valve I50 with it in initially unchanged relative positions, due to the downward pressure of the high pressure fluid in the high pressure chamber 50, the unchanged relative positions being indicated by the horizontal lines 30I and 40I in Fig. 25. At a point near the end of the descending stroke of the motor plunger 83, the lower margin of the striker sleeve I60 on the pilot valve rod II makes contact with the upper surface of the nipple 48,

arresting the descent of the pilot valve and so mechanically causing the movement of the pilot valve relative to the motor plunger and the main valve which is indicated by the sloped line 402 annular channel I8 I, fluid in the upper pilot valve' chamber I55 will flow through the pilot valve by-pass I82 to the lower pilot valve chamber I50, and, thereafter, it will be ejected through the radial orifices I19 and the longitudinal groove I80 and the lower vent passage I60 to the production tubing 34. Immediately after the shoulder I53 of the pilot valve piston head I52 has been passed by the annular channel IN, and

has thus cut off communication between the upper pilot valve chamber I55 and the lower pilot valve chamber I56, the lower pilot valve port I15 comes into registry with the pilot valve control channel I84, as shown in Fig. '7, permitting a flow of high pressure fluid to the lower pilot valve chamber I56 through the control channel I84, the v annular channel I83, and the pilot valve by-pass passage I82. This high pressure fluid in the lower pilot valve chamber I5'6, acting in opposition to the relatively low pressure fluid in the vented upper pilot valve chamber I55,'hydraulically causes upward movement of the pilot valve, disengaging the striker sleeve I60 from the upper surface of the nipple 48. The accelerated upward movement of the pilot valve relative to the motor plunger 83 is indicated by the steeply 3 sloped line 403 of Fig. 25. It is, of course, of only momentary duration, as the pilot valve piston head I52 almost immediately completes its traverse of the bore I44 and comes into contact with the shoulder I45, and the pilot valve and motor plunger necessarily move thereafter in unison, as indicated by the horizontal line 404 in Fig. 25, but it serves to permit the pilot valve to actuate the main valve I20 before the motor plunger has reached the mechanical limit of its stroke,'as will now be described.

As the pilot valve I50 moves upwardly relative to the motor plunger 83, the initial mechanically forced stage of this movement causes the upper pilot valve port I13, initially open to the upper main valve chamber I25, to pass within the upper plug 86 and to be closed thereby, and causes the lower spanning groove "2 to pass wholly within the lower valve chamber. Both upper and lower main valve chambers are thus momentarily closed to either ingress or egress of operating fluid, and the main valve I20 continues to move in unison with the motor plunger 03. The accelerated, hydraulically forced stage of movement of the pilot valve relative to the motor plunger 83 causes the upper spanning groove I68 to connect the upper main valve chamber I25 to the upper vent passage I65, as shown in Fig. 8, releasing the fluid in the upper main valve chamber I25 to the production tubing 34, and opens the intermediate pilot valve port I" to the lower main valve chamber I24, admitting high pressure fluid thereto from the axial passage I51 of the pilot valve. The upwardly actingpressure differential thus created between the lower and upper main valve chambers moves the: main valve I20 rapidly upward, as illustrated by the portion 302 of the graph of Fig. 25, the en tire movement occurring during the latter por tion of the hydraulically forced movement of the pilot valve and the initial portion of the subsequent movement in unison of the pilot valve and the motor plunger.

Although the above-described movement of the main valve is rapid and of short duration, it is, nevertheless, controlled both as to accelera tion and deceleration. As shownin Fig. 7, prior to the upward movement of the main valve,'the bleeder passage I4I, bleeder groove I42, and the helical groove I40 form a channel of communica-. tion between the lower main valve chamber I24 and the radial ports I38 leading to the lower plunger longitudinal passages II3. This channel temporarily serves to release any high pressure fluid which may leak along the exterior of the pilot valve I50 to the lower valve main chamber I24 after the lower spanning groove II2 has ceased to communicate between the lower main valve chamber I24 and the lower vent passage I68, and so serves to prevent premature lifting of the main valve I 20. As the main valve I20 begins its upward movement, the bleeder groove I42 intercepts a progressively shorter length of the helical groove I40, resulting in decreasing resistance to the release of pressure therethrou gh and so controlling the acceleration of the main valve. Toward the conclusion of the upward stroke of the main valve, deceleration is accomplished b dashpot action of the restricted radial orifice I31. The shoulder I23, as it ascends,

forces fluid ahead of it toward the radial orifice I 38 and the restricted radial orifice I3'I. When the shoulder I23 has passed beyond the radial orifice I36, the fluid remaining in the bore 34 above the shoulder I23 can escape only through the restricted radial orifice I3'I, as shown in Fig. 8, and the final upward movement of the main valve is thereby hydraulically cushioned. The ascending motion of the main valve I20 relative to the motor plunger 83 is indicated in Fig. 25 by the ascending line 302 curved terminally to illustrate the acceleration and deceleration of the valve.

The upward motion of the main valve I20 first closes communication between the alternating pressure chamber 9| and the plunger discharge ports II5, thus preventing escape of spent operating fluid from below the motor plunger 83 and arresting the descent of the motor plunger, and then opens communication between the high pressure chamber 50 and the alternating pressure chamber 9|, thus permitting high pressure operating fluid to flow into the latter and to cause the motor plunger to move upwardly on its upstroke. Both of these actions are so governed as to prevent overly abrupt deceleration and acceleration of the motor plunger. As soon as the main valve I20 begins its ascent from the position shown in Fig. 7, the main valve bridge channel I34 begins to move out of registry with the lower terminal annular groove II4, reducing the opening available for the escape of spent operating fluid which is forced from the alternating pressure chamber 9| by the descending motor plunger. This closure is, however, performed gently and in the manner obviating shock because of the governing groove I35 which follows the main valve bridge channel I34 across the lower terminal groove H4 and effects a gradual closure thereof. The speed of closure is further regulated by the above-mentioned gradual acceleration of the main valve I20. The motor plunger 83 is consequently brought to a hydraulically cushioned stop as indicated by the curved line 202 in Fig. 25.

' In the final stage of the upward movement of the main valve I20, the longitudinal valve pas.- sages I enter into registr with the upper and lower plunger longitudinal passages I09 and H3, respectively, as shown in Fig. 8, and permit the flow of high pressure fluid from the high pressure chamber 50 to the alternating pressure chamber 8|. This opening of communication is gradual because the velocity of the main valve I20 is decelerated by the dashpot action of the restricted radial orifice I31, as heretofore described, and also because the initial opening is effected by registering of the throttling groove I32 with the upper terminal annular groove IIO.

With high pressure fiuid admitted to the alternating pressure chamber 9|, the motor plunger 83 now has high pressure fluid and low pressure fluid acting upon it in both upward and downward directions. High pressure is exerted downwardly, as before, on the cross-sectional area of the tubular piston rod 88, but is more than ofiset by high pressure in the alternating pressure chamber OI exerted upwardly on an annulus having the crosssectional area of the motor plunger head 84 less the cross-sectional area of the connecting rod I03. Low pressure is exerted upwardly on the connecting rod I03, but is more than offset by low pressure in the motor discharge chamber 90 exerted downwardly on an annulus having the cross-sectional area of the motor plunger head 84 less the cross-sectional area oithe tubular piston rod 88. The net, or unbalanced, area affected by upwardly exerted high pressure equals the net, or unbalanced, area afiected by downwardly exerted low pressure, and the net effect is, of course, to cause the motor plunger 83 to begin its ascending stage of the cycle of reciprocation.

It will be seen that with the piletamlve piston head I52 engaged by the shouldef IiIgpi the lower plug 98 so hat the pilot valve licmoves in unison with the motor plunger 83, as indicated by the horizc htal line 404 of Fig. 25, the descending stroke of: the motor plunger 83 would be limited by contact of the striker sleeve I60 with the upper surface of the nipple 48. However, the action of the main valve I20 is such that, normally, even though terminal movement of the main valve is cushioned, high pressure fluid is admitted to the alternating pressure chamber 9I in time to reverse the direction of movement of the motor plunger 83 before the mechanical limitation is effective. Theoretically, a momentary pause would occur at the end of the motor plunger stroke, indicated in Fig. 25 at 203, having a duration equal to the time of travel of the main valve I20 from the position in which the discharge of spent operating fluid through the lower plunger longitudinal passages H3 is cut off to the position in which high pressure operating fluid is admitted to the lower plunger longitudinal passages. In practice, it will be found that due to inertia of the moving parts, or to compressibility of the operating fluid, no such pause occurs, or at most it is of practically imperceptible duration, and the motor plunger passes smoothly from the decelerating movement indicated at 202 to the accelerating movement of the reverse stroke indicated at 204, produced by the above-described gradual admission of high pressure fluid to the lower plunger longitudinal passages H3 and then to its ascending stroke indicated by the line 205 in Fig. 25.

As the motor plunger 83 starts upwardly, the pilot valve I50 and main valve I20 accompany it, due to high pressures existing in the lower pilot valve chamber I56 and lower main valve chamber I24, and to low pressures existing in the lower and upper vent passages I69 and I65 to which the upper pilot valve chamber I55 and the upper main valve chamber I25 are then open. The absence of relative movement is indicated by the horizontal lines 404 and 303 in Fig. 25. At a point near the end of the ascending stroke of the motor plunger 83, the striker sleeve I60 strikes the upper tubular fitting 31 and is arrested thereby, so mechanically causing the movement of the pilot valve relative to the motor plunger and the main valve, which is indicated by the sloped line 405 in Fig. 25. As illustrated in Fig. 9, as the motor plunger 83 and the main valve I20 continue to ascend, the lower pilot valve port I15 passes downwardly beyond the lower end of the pilot valve control channel I84 and is closed by the bore I44. The upper shoulder I53 of the'pilot valve piston head I52 at once comes into registry with the annular channel I8I, allowing the fluid in the lower pilot valve chamber I56 to escape through the pilot valve by-pass I82 and the upper pilot valve chamber I55 to the lower vent passage I69. Until then this fluid has been forced by the descending pilot valve to return to the axial valve passage I 51. During this mechanically forced movement of the pilot valve, the intermediate pilot 17 a valve port I14 passes'downwardly out of registry with the lower main valve chamber I24 and is closed by the bore I43 in the lower plug 98.

With the fluid in the lower pilot valve chamber I free to escape through the lower vent passage I99, the high pressure operating fluid in the high pressure chamber 50 urges the pilot valve I20 downwardly. The striker sleeve I60 is disengaged from the upper tubular fltting 31, and the pilot valve is hydraulically moved downwardly, while the motor plunger continues to move upwardly. The accelerated movement of the pilot valve relative to the motor plunger is indicated by the steeply sloped line 406 of Fig. 25, and the relative positions of the valves and motor plunger at the instant that hydraulic actuation of the pilot valve begins are shown in Fig. 9. As in the case of the upward, hydraulically urged motion of the pilot valve, hereinbefore described, this accelerated downward movement of the pilot valve is of brief duration, and the pilot valve piston head I52 comes into contact with the plug IOI, causing the pilot valve and the motor plunger to move thereafter in unison, as indicated by thehorizontal line 401 of Fig. 25. and completing the cycle of the pilot valve.

The hydraulically actuated downward movement of the pilot valve I50 brings the upper pilot valve port I13 into registry with the upper main valve chamber I25, admitting high pressure operating fluid thereto from the axial valve passage I51. The lower spanning groove I12 is immediately thereafter brought into communicating position between the lower main valve chamber I24 and the lower vent passage I69, releasing the fluid below the main valve I20 and permitting the main valve to descend in response to the fluid pressure above it. It should be noted that, while the main valve I20 has been in its raised position, shown in Figs. 8 and 9, the lower main valve chamber I24 has been in communication with the lower plunger longitudinal passages H3, which, for the moment, contain high pressure fluid, through the helical groove I40 and the radial ports I39. As long as the intermediate pilot valve port I14 is open to the lower main valve chamher, the pressures at each end of the helical groove I40 are equal, but when the intermediate pilot valve port is closed by the descent of the pilot valve, the helical groove I40 provides pressure from the lower plunger longitudinal passages I I3 to compensate for any leakage from the lower main valve chamber to the lower vent passage I 69 until flow through the lower spanning groove I12 overcomes it. The main valve I20 is thus protected against a premature descent, but the pressure upholding it may be quickly overcome when the operating cycle so requires because of the resistance provided by the helical groove I40.

The main valve I20 now descends in response to the high pressure above it, its course being indicated in- Fig. 25 by the curved line 304. For

the moment, the velocity of the main valve is retarded by the dashpot action in the bore 94 exerted by the shoulder I23, which, until it passes and permits opening of the radial orifice I36, creates a partial vacuum through the restricted radial orifice I31. Thereafter, the main valve descends rapidly until the annular bleeder groove I 42 is in registry with the radial ports I39. The eifective flow areas of the annular bleeder groove sure from the lower plunger longitudinal passages ll3 builds up pressure in the lower main valve chamber I24 faster than pressure is released therefrom through the lower spanning groove I12 and the vent passages connected thereto. Consequently, the descending movement of the main valve I20 is momentarily decelerated. This feature of the invention has special importance if the pump load is suddenly lightened, as by the advent of gas in the well fluid, as it prevents unduly rapid acceleration of the motor plunger 03 under such circumstances.

During the initial accelerating stage of the descent of the main valve I20, the longitudinal valve passages I30 are moved out of'registry with the upper and lower plunger longitudinal passages I09 and H3, respectively, cutting oil! the supply of high pressure operating fluid to the alternating pressure chamber 9|. The rate of flow is decreased gradually by the accelerating movement of the main valve and by the gradual closure of the upper terminal groove IIO by the I42 and the bleeder passage I are greater than i the effective flow area of the radial port I1I connecting them with the lower vent passage I69. A dashpot efiect is thereby imposed, and high presthrottling groove I32. The resultant deceleration of the upward movement of the motor punger 83 is indicated by the curved line 206 in Fig. 25.

The motor plunger then theoretically pauses, as.

indicated at 201, while the main valve moves rapidly to the position in which the main valve bridge channel I34 connects the lower plunger longitudinal passages I I3 to the plunger discharge ports I I5, the pause being practically imperceptible because of the inertia of the motor plunger.

The connection between the lower plunger longitudinal passages H3 and the plunger discharge ports H5 is made gradually, both because of the deceleration of the main valve at this stage of its movement and because communication is initially opened by the governing groove I35. Consequently. the motor plunger 83 accelerates gradually, as indicated at 208 in Fig. 25, as it begins to repeat the described cycle. 1

The pump unit 32 reciprocates in unison with the motor unit 3|, being attached thereto by the connecting rod I03, but its cycle of reciprocation will be described in the reverse order of strokes.

On the upstroke of the motor plunger 03, the

pump plunger head I92 is drawn upwardly in the pump inlet chamber 00, creating a partial vacuum therein and causing compression within the pump plunger I90 and the pump discharge chamber 10, and thereby causing the travelling valve I94 to close and the standing valve "to open. Well fluid already-in the pump discharge chamber 10 is discharged therefrom through the discharge ports H to the production tubing 34, the reduction in capacity of the pump discharge chamber being proportionate to the differential in cross-sectiional area of the pump plunger tube I90 entering the pump discharge chamber and the connecting rod I03 withdrawn therefrom. Well fluid is drawn into the pump inlet chamber from the well casing 36 through the standing valve 11,, the increase in capacity of the inlet chamber being proportionate to the cross-sectional area of the pump plunger head I92. On the reverse or downward stroke of the pump plunger, the standing valve 11 is closed by back pressure, and the travelling valve I94 is opened. Well fluid is forced from the pump inlet chamber 80 through the travelling valve I94 into the interior space I96 of the pump plunger head I92 and into the interior space I 91 of the pump plunger I and thence through the discharge ports I98 into the pump discharge chamber 10. As the decrease in capacity of the pump inlet chamber 30 on the downward stroke of the pump is proportionate to the cross-sectional area of the pump'plunger head I92, and the increased capacity of the pump discharge chamber is proportionate only to the cross-sectional area of the pump plunger I90 less the cross-sectional area of the connecting rod I03, well fluid is necessarily forced from the pump discharge chamber to the production tubing 34 by the downward stroke of the pump plunger as well as by the upward stroke thereof. A discharge of well fluid from the discharge ports 'II will occur on both strokes of the pump, provided the increased capacity of the discharge chamber on the downward stroke of the pump is less than the reduced capacity of the inlet chamber on that stroke.

It will be seen, therefore, that the operation of my pumping apparatus is double-acting for both the motor and the pump. Both strokes of the motor are power strokes, and both strokes of the pump are discharge strokes. Both strokes of the motor also result in the discharge of spent operating fluid to the production tubing. Both the motor and the pump have differential type reciprocating plungers. The chambers respective to each of the plungers are alternately disconnected and in connected series and are so arranged that the last cylinder in each series is 25 that the pilot valve I50 and the main valve- I20 are stationary relative to the motor plunger 33 during the period of maximum fluid discharge from the motor and from the pump, and that they are moved and therefore the fluid actuating them is discharged at the brief period of minimum discharge from the motor plunger and the pump. This action lessens the amplitude of the pulsations in the production tubing and is thereby conducive to conservation of power. It is supplemented by Jets of high pressure operating fluid discharged from the upper and intermediate pilot valve ports I13 and I" through the upper and lower vent passages I65 and IE9 as those ports pass those passages in their upward and downward "movements. The discharge of operating fluid outwardly through the motor discharge ports 02 to the production tubing 34 is continuous, and well fluid cannot enter the ports 62 against this discharge. This prevents the entry of sand or other foreign materials into the working parts of the motor, which is an important feature of my invention. If foreign matter were able to enter the ports 62, it could not have access to the working parts of the motor except through the narrow annular channel 06, and this annular channel is continuously flushed upwardly toward the ports 62 as it'receives spent operating fluid from the plunger discharge ports H5 during downward movement of the motor plunger and is reduced in capacity by upward movement of the motor plunger and receives fluid from the vent passages I63 and I39 at each end of the plunger stroke.

The combined action of the double-acting differential fluid-operated motor with the doubleacting diflerential plunger pump thus not only economizes on power by providing a relatively.

the pump. The hydraulically actuated main valve I20 and the partly hydraulically actuated pilot valve I 50 provide continuity to the outflow of operating fluid through the motor discharge ports. The discharge from these valves is potentially of higher pressure than the spent operating fluid discharged through the plunger discharge ports II5, as it has less work to perform, and, in conjunction with the high pressure jets emitted through the vent passages I and IE9 as the latter are passed by the pilot valve ports I13 and I14, it maintains a substantial velocity of the fluid through the annular channel 36 and the motor discharge ports 62 at periods when the velocity would otherwise be at a minimum.

Also, as will now be shown, the combination of a differential type motor with a pump of the differential plunger type, hereinbefore described,

permits proportionment of the pump discharge and the fluid-operated motor discharge so as to readily obtain the greatest economy of operation in wells of different depths, pressures, and rates of flow.

The ratio of power generated by the motor unit 3I to the volume of operating fluid supplied thereto at a given pressure may be altered by changing the cross-sectional areas of the tubular piston rod 33 and the connectingrod I03 with reference to the cross-sectional area of the motor plunger head '84, the latter being considered more or less determined by spatial limitations. Likewise, the apportionment between upward and downward pump strokes of the double-stroke discharge of the pump unit 32 may be altered by changing the cross-sectional areas of the connecting rod I03 and the pump plunger I90 with reference to the cross-sectional area of the pump plunger head I 92 which determines the double-stroke discharge for a given length of stroke. It will be seen that the cross-sectional area of the connecting rod I03 is a factor in both of these alterations. It will also be seen that the tubular piston rod 33, motor plunger head 84, connecting rod I03, pump plunger- I90, and pump plunger head I92 are threadedly connected and that the liners through which they slide are held by the clampingaction of adjacent parts of the jacket 33. It is, therefore, a relatively simple operation to alter the power and discharge characteristics of my invention to suit well conditions 'by the substitution of motor plunger parts, connecting rods, and pump plunger parts of the desired size, with concomitant changes in the liners.

While regulation of power ratios and fluid discharge ratios may be made in the above-described manner by changes in cross-sectional areas which by high pressure operating fluid and spent operating fluid is always equal to the cross-sectional area of the tubular piston rod 88 on both upward and downward strokes of the motor, and the power so derived is consequently equal on both strokes. The cross-sectional area of the connecting rod I03 should always be less than that of the tubular piston rod 88 in order to provide'a continuous discharge of operating fluid from the motor unit 3 I.

It will be found that when a condition of balanced power prevails on the upward and downa pump plunger I98 having a cross-sectional area equal to one-half the cross-sectional area of the pump plunger head I92 and ignoring the displacemy invention to be accorded the full scope of the following claims.

I claim as'my invention:

1. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of a pumping unit having a reciprocable differential-type pump plunger and adapted to discharge fluid into said conduit means on both strokes of reciprocation; a reciprocating differential-type fluid-operated motor operably connected to said pump plunger to cause reciprocation of the same and having a discharge chamber for receiving spent operating fluid and outlet means from said discharge chamber to said conduit means, said motor beingadapted to cause 1 versal .of said motor adapted to discharge spent j I operating fluid to said discharge chamber at the ment effect of the connecting rod N3 in thepump discharge'chamber 10. A discharge of the pumpunit 32'is thus obtained, unbalanced by twice the maximum displacement of the connecting rod I03, which will combine with the unbalanced discharge of the motor unit 3i to provide a balanced total discharge under conditions of balanced application of power.

While irregularity in the speed of the pump, caused by unbalanced power and load factors,

has no serious consequences during the major portion'of each stroke, it may be detrimental if permitted to affect the rate 'of deceleration and as hereinbefore described, controlled independently of the degree of power applied to the motor plunger, the power may be proportioned to the forconveying a product therefrom, the combina end of each stroke of reciprocation of said motor so as to cause continuous discharge of said spent. operating fluid through said outlet meanstosaid conduit means; means for controlling the rate of' operation of said valve means; and means for.

controlling the deceleration and acceleration of said motor.

2. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means tion of a pumping unit having a reciprocable pump plunger and adapted to discharge fluid into said conduit means on both strokes of reclprocation; a reciprocating fluid-operated motor operably connected to said pump plunger to cause reciprocation of the same and having a discharge chamber for receiving spent operating fluid and outlet means from said discharge chamber to said conduit means, said motor being adapted to cause a discharge of spent operating fluid through causing'reversal of said motor adapted to discharge spent operating fluid to said discharge pump load as desired, without danger. Each of these factors-the control of the rate of reversal and the control of speed during the major portion of each strokeis independent of the other and V subject to dashpot action to control its speed, andthe main valve is in turn actuated by a pilot valve having mechanical initiation of movement and hydraulic acceleration, an exceptional range of speed is possible. A speed as low as two strokes per minute may be attained without stalling or binding. 0n the other hand, thirty to forty strokes per minute are possible without endangering the rapidly reciprocating parts.

Although I have herein shown and described a simple and practical embodiment of my invention, it will be understood that numerous details of construction, proportion, and arrangement may be modified without departing from the spirit of my invention, and I- do not intend to be limited to these details as herein disclosed, but intend chamber at the end of each stroke of reciprocation of said motor so as to cause continuous discharge of said spent operating fluid through said outlet means to said conduit means.

3. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combinae tion of: a pumping unit having a reciprocable pump plunger and adapted to discharge fluid into said conduit means on both strokes of reciprocation; and a reciprocating fluid-operated motor operably connected to said pump plunger to cause reciprocation of the same and having a discharge chamber for receiving spent operating fluid and outlet means from said discharge chamber to said conduit means, said discharge chamber and said outlet means forming a flow channel of substantial length between said motor and said conduit means, and said motor being adapted to cause a continuous discharge of spent operating fluid through said flow channel.

4. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of: a pumping unit having a reciprocable differential-type pump plunger and adapted to discharge fluid into said conduit means on both strokes of reciprocation; a reciprocating differential-type fluid-operated motor operably connected to said pump plunger to cause reciprocation of the same and having a discharge chamber for receiving spent operating fluid and outlet means from said discharge chamber to said conduit means spaced from said motor, said motor being adapted to cause a discharge of spent operating fluid through said outlet means on both strokes of reciprocation; and means for discharging operating fluid to said discharge chamber at the end of each stroke of reciprocation of said motor so as to cause continuous discharge of operating fluid through said outlet means to said conduit means.

5. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of: a pumping unit having a reciprocable differential-type pump plunger and adapted to discharge fluid into said conduit meanson both strokes of reciprocation; a reciprocating differential-type fluid-operated motor operably connected to said ,pump plunger to cause reciprocation of the same and adapted to discharge spent operating fluid to said conduit means synchronously with the discharge of fluid thereto by said pumping unit; and means for discharging additional operating fluid from said motor at the end of each stroke of reciprocation thereof so as to cause continuous discharge of operating fluid therefrom to said conduit means.

6. In a fluid-operated pum-p having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of a pumping unit having a reciprocable differential-type pump plunger and adapted to discharge fluid into said conduit means on both strokes of reciprocation; a fluid-operated motor including a reciprocating differential-type motor plunger operably connected to said pump plunger to cause reciprocation of said pump plunger and adapted to discharge spent operating fluid from said motor to said conduit means during each stroke ofreciprocation; and fluid-operated valve means for causing reversal of the direction of movement of said motor plunger adapted to discharge operating fluid at the end of each stroke of reciprocation of said motor plunger in commixture with the operating fluid discharged by said motor plunger and to cause a continuous flow of the so commixed operating fluid from said motor to said conduit means.

7. In a fluid-operated pump having supply means for supplying relatively high .pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of: a fluid-operated motor including, in alignment, a high pressure chamber communicating with said supply means, a discharge chamber communicating with said conduit means, and a third chamber forming a motor cylinder jointly with said discharge chamber; a motor plunger reciprocable in said motor cylinder having a piston extending from its one side into said high pressure chamber and a rod extending from its other side through the distal end of said third chamber; and valve means for opening said third chamber alternately to communication with said high pressure chamber and said discharge chamber so as to cause reciprocation of said motor plunger, said piston having a cross-sectional area less than that of said motor plunger and greater than that of said rod, whereby reciprocation of said motor plunger in either direction causes the contents of said discharge chamber to flow to said conduit means.

8. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit'means for conveying a product therefrom, the combination of: a fluid-operated motor including, in alignment, a high pressure chamber communicating with said supply means, a discharge chamber communicating with said conduit means, and a third chamber forming a motor cylinder jointly with said discharge chamber; a motor plunger reciprocable in said motor cylinder; and valve means for opening said third chamber alternately to communication with said high pressure chamber and said discharge chamber so as to cause reciprocation of said motor plunger, said valve means and said motor plunger forming restricted passage means for said operating fluid adapted to cause gradual opening and closing of communication between said third chamber and said discharge chamber so as to cause gradual acceleration and deceleration of said motor plunger when said motor plunger is moved toward said third chamber.

9. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of: a fluid-operated motor including, in alignment, a high pressure chamber communicating with said supply means, a discharge chamber communicating with said conduit means, and a third chamber forming a motor cylinder jointly with said discharge chamber; a motor plunger reciprocable in said motor cylinder; and valve means for opening said third chamber alternately to communication with said highpressure chamber and said discharge chamber as to cause reciprocation of said motor plunger, said valve means and said" motor plunger forming restricted passage means for said operating fluid adapted to cause gradual opening and closing of communication between said high pressure chamber and said third chamber so as to cause gradual acceleration and deceleration of said motor plunger when said motor plunger is moved toward said high pressure chamber.

10. In a fluid-operated pump having supply means for supplying relatively 1 high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of: a fluid-operated motor including, in

alignment, a high pressure chamber communicating with said supply means, a discharge chamber communicating with said conduit means, and a third chamber forming a motor cylinder jointly with said discharge chamber; a motor plunger reciprocable in said motor cylinder; and valve means for opening said third chamber alternately to communication with said high pressure chamber and said discharge chamber so as to cause reciprocation of said motor plunger, said valve means and said motor plunger forming restricted passage means for said operating fluid adapted to cause gradual opening and closing of comasemsa r a third chamber forming a motor cylinder jointly with said discharge chamber; a motor plunger reciprocable in said motor cylinder; fluidoperated reciprocating valve means for opening said third chamber alternately to communication with said high pressure chamber and said discharge chamber so as to cause reciprocation of said motor plunger; and means forming dashpots at each end of said valve means for so delaying the movement of said valve means in each direction of reciprocation as to require 'substantially a predetermined period-of time for the completion of said movement.

'26 1 said motor plunger through said motor discharge chamber and into said high pressure chamber; a rod extending from the other side of said motor plunger through the distal end of said third chamber and into said pump discharge chamber and there operatively connected to said extension to cause reciprocation of said pump plunger, said piston having a cross-sectional area greater than that of said rod and less than that of said extension and equal to one-half the difference in cross-sectional area of said motor plunger and said rod; and valve means for opening said third chamber alternately to communication with said hish pressure chamber and said motor discharge chamber so as to cause reciprocation of said motor plunger.

14. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of: a fluid-operated motor including,"in alignment, a high-pressure chamber communicating with said supply means, a discharge chamber communicating with said conduit means, and a third chamber forming a motor cylinder jointly with said discharge chamber; a motor plunger reciprocable in said motor cylinder having a pis- 12. In a fluid-operated pump having supply extending from its one side into said high pressure chamber and a rod extending from its other side through the distal end of said:third chamber; and valve means for opening said third chamber alternately to communication with said high pressure chamber and said discharge chamber so as to cause reciprocation of said motor plun er, said piston having a cross-sectional area less than that of said motor plunger andgreater than that of said rod and equal to one-half the difference in cross-sectional area of said motor plunger and said rod.

13. In a fluid-operated pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, the combination of: a reciprocating pumping unit having an inlet chamber and a pump discharge chamber; a pump plunger reciprocable in said inlet chamber; inlet means for said inlet chamber; outlet means in said pump discharge chamber communicating with said conduit means; valve means operable to permit fluid flow through said inlet means to said inlet chamber and from said inlet chamber to said pump discharge chamber; an extension on said pump plunger having a cross-sectional area equal to one-half the crosssectional area of said pump plunger and extending from said pump plunger into said pump discharge chamber; a fluid-operated motor including, in alignment, a high pressure chamber communicating with said supply means, a motor discharge chamber communicating with said conduit means, and a third chamber forming a motor cylinder jointly with said motor discharge chamber; a motor plunger reciprocable in said motor cylinder; a piston extending from one side of ton removabl connected to its one side and extending into said high pressure chamber, and a rod extending from itsother ride through the distal end of said third chamber; and valve means for opening said third chamber alternately to communication with said high pressure chamber and said motor discharge chamber soas to including, in alignment, 9, high. pressure chamber communicating with said supply means,.'a

discharge chamber communicating with said conduit means, and a third chamber forming a motor cylinder jointly with said discharge chamber; a motor plunger reciprocable in said motor cylinder having a piston, connected to its one side and extending into said high pressure chamber, and a rod extending from its other side through the distal end of said third chamber and into said pumping unit and there operatively connected to said pump plunger to cause reciprocation thereof, said pumping unit having a pump discharge chamber adapted to receive said rod, and said pump plunger having a portion of greater cross-sectional area than said rod extending into said pump discharge chamber and there connected to said rod; and valve means for opening said third chamber alternately to communication with said high pressure chamber and said motor discharge chamber so as to cause reciprocation of said motor plunger.

16. A fluid-operated motor for a pump having supply means for supplyingrelatively high pressure operating fluid thereto and having conduit means for conveying a product therefrom, comprising: cylindermeans including a discharge chamber open to said conduit means; a diflerential-type plunger reciprocable in said cylinder means in response to the pressure of said operating fluid and adapted to cause a discharge of spent operatingriuid from said discharge cham- 27 her on both strokes of reciprocation; a fluidoperated main valve for causing reciprocal move- I ment of said plunger; and a pilot valve for supplying fluid to actuate said main valve, responsive to movement of said plunger to move through an initial stage of movement to a position in which it is adapted to hydraulically actuate its own further movement, and then responsive to such hydraulic actuation to move at increased velocity to a position in which it is adapted to actuate said main valve.

17. A fluid-operated motor for a pump having means for conveying a product therefrom; comprising: cylinder means including a discharge chamber open to said conduit means; a difierential-type plunger reciprocable in said cylinder means in response to the pressure of said operating fluid and adapted to cause a discharge of spent operating fluid from said discharge chamber on both strokes of reciprocation; and valve means interconnecting said cylinder means for causing supply means for supplying relatively high presciprocable valve means for causing reciprocal movement of said plunger; and means forming dashpots at each end of said valve means for so delaying the movement of said valve means in each direction of reciprocation as to require substantially a predetermined period of time for the completion of said movement.

18. A fluid-operated motor for a pump having supply means for supplying relatively high pressure operating fluid thereto and having conduit said operating fluid to actuate said plunger, said valve means and said plunger forming restricted passage means for causing a gradual increase and decrease in the rate of flow 0! said operating fluid at the beginning and end of each reciprocating stroke of said plunger so as to cause gradual acceleration and deceleration of said plunger.

MURRAY F. ECKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number I Name Date 1,031,340 Howard July 2, 1912 1,577,971 Humphreys Mar. 23, 1926 1,745,566 Yerkes Feb. 4, 1930 1,764,473 Scott et a1. June 17, 1930 1,828,857 Coberly Oct. 27, 1931 1,848,070 Archer Mar. 1, 1932 2,331,151 Williams Oct. 5, 1943 

